import matplotlib.pyplot as plt

import numpy as np 

x = np.linspace(-4, 4, 50)
y1 = 3 * x + 4
y2 = x ** 2
#create first map
plt.figure(num=1, figsize=(7,6))
plt.plot(x, y1)
plt.plot(x, y2, color="red", linewidth=3.0, linestyle="--")

#create second map
plt.figure(num=2)
plt.plot(x, y2, color="green")

plt.show()